The present invention is concerned with connector pins that are adapted to be pushed into a metallized bore formed in at least one electrically conductive plate, to produce a solder-free connection between the pin and the plate. The form of pin with which the present invention is particularly concerned is one wherein the pin has a deformable region, adapted to engage the sides of the bore in the conductive plate, consisting of two spaced and generally parallel beam members the outer edges of which are adapted to mechanically and electrically engage the walls of the bore.
Connector pins, adapted to be pressed or pushed into a bore in a conductive plate, have been suggested heretofore. In one known configuration, the pin is provided with a region that is substantially square or rectangular in cross section and which is intended, when the pin is inserted into the metallized bore of a conductor plate, to engage at its outer edges the metallized wall of the bore. Since the bore diameter and the cross sectional dimensions of the aforementioned region of the pin vary, a secure contact between the pin and bore walls is not always attainable. This is particularly true when a single pin is pressed through aligned bores in a plurality of superposed conductor plates. Moreover, when a pin is so pressed through the bores of superposed conductor plates, it is normally intended that the pin not only make electrical connection to each of said plates but that, in addition, it should act to hold the plates together mechanically; and such a mechanical connection cannot be assured due to the aforementioned dimensional variations.
So-called AMP pins have been suggested in which the region of the pin that is adapted to engage the walls of the bore consists of two parallel beam-shaped elements which are separated from one another and partly overlap one another adjacent the middle of the pin. When such a pin is pressed into the bore of a conductor plate, the beam-shaped members move relative to one another whereby relatively large dimensional variations of the bore can be compensated by this particular region of the pin. A disadvantage of this particular structural arrangement, however, is that only two outer edges of the contact region of the pin, lying diagonally opposite one another, engage the wall of the bore. Since each beam-shaped element is, in effect, clamped in position at its opposing ends in the direction of the axis of the pin, and since each beam-shaped element accordingly bends when the pin is inserted into the bore of a plate, problems can occur with respect to the reliability of the mechanical or electrical connection that is achieved at the contact zone of the pin, particularly in those cases where the pin is inserted through a plurality of superposed conductor plates.
In another known form of connector pin, the contact zone of the pin consists of a tube that is slotted lengthwise. When such a pin is pressed into the bore of a conductor plate, the arc-shaped portions of the contact zone bend inwardly. As a result, a region of substantially flat contact exists between the wall of the bore and the side walls of the tubular section, and this tends to impair the transition resistance between the pin and bore when the bore wall and/or the surface of the contact region of the pin has a layer of increased ohmic resistance. More particularly, in this particular arrangement the metallized layer of the bore wall is not penetrated by any portion of the contact region of the pin. This problem becomes particularly pronounced when the pin is to be inserted through a plurality of superposed conductor plates inasmuch as, in such an arrangement, good electrical and/or mechanical connection between the pin and all of these plates cannot be assured.
A still further arrangement is disclosed in European Pat. No. 5,356 (corresponding to Keim U.S. Pat. No. 4,274,699) wherein a pin is provided with thick, non-deformable outer zones having an exterior arcuate contour which corresponds to the inner contour of the bore that receives the pin. These outer zones are connected to one another by a thin cross piece which is plastically deformed and/or sheared off when the pin is set into the bore. The arcuate exterior of the outer zones lies against the wall of the bore without, however, penetrating the tin layer of the wall of the bore; and this arrangement therefore again results in the problems discussed above. Moreover, the complete plastic deformation or shearing off of the cross piece is especially disadvantageous, since this results in a loss of the elasticity needed to securely press the outer contour of the outer zones of the pin against the wall of the bore after the pin has been set into the bore. This disadvantage becomes particularly pronouned if any mechanical loading is applied to the pin and/or if the pin or bore are subject to vibratory stresses. The pin of this particular arrangement is also unsuitable for connecting two or more conductor plates together since insertion of the pin into the bore of a first conductor plate causes the complete plastic deformation or shearing off of the cross piece, and the pin cannot therefore firmly engage the bore of a second conductor plate unless the bore in the second plate has a diameter less than the diameter of the bore in the first conductor plate.
The present invention is intended to avoid these problems in the prior art by providing a pin configuration which can compensate for variations of tolerance of the bore and/or contact zone of the pin, thereby to always assure an excellent electrical and mechanical connection between the pin and conductor plate regardless of whether the pin is to be inserted into a single plate or through a plurality of superposed conductor plates.